STAT5 phosphorylation is prolonged in cells expressing DUB-2.

(A) Ba/F3β (Ba/F3 cells expressing the IL-2Rβ) cells were stimulated with IL-2 for 20 minutes, then removed from cytokine and incubated in cytokine-free medium as indicated. Lysates were immunoprecipitated with anti–IL-2Rβ, anti-STAT5b, or anti-FLAG M2, and immunoblotted with antiphosphotyrosine (pY), anti–[IL-2Rβ, anti-STAT5b, or anti-FLAG as indicated. (B) Ba/F3β/tTA DUB-2 were grown with or without tetracycline (+/− Tet) for 48 hours and stimulated with IL-2 for the indicated times. Lysates were immunoprecipitated with anti-STAT5b and immunoblotted with antiphosphotyrosine (pY) or STAT5b antisera as indicated. Whole cell lysates were also run on SDS-PAGE and immunoblotted with DUB-2 antiserum.